Creating a thread which acquires a mutex before the calling thread in C++0x

I have the following situation

std::mutex m;

void t() {
    //lock the mutex m here
}

main() {
    //create thread t here
    //lock the mutex m here
}

I would like the thread t() to acquire the mutex before main(), how can I obtain this behaviour using the threading functions provided by C++0x? Putting simply an std::lock_guard inside main() and t() would not work because it can take a bit before the thread is spawned, an so the mutex can be locked by main().